Photographic color process



March 7, 1933. M, w, SEYMQUR 1,900,870

PHOTOGRAPHIC COLOR PROCESS Filed April 26, 1932 j l, BM@e&Silver image. Lg-5 1' A-Bluegzjeezz/dye c .Silver mage.

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20 remove i Patented Mar. 7, 1,933

UNITED ysfr-Mas PArENii ori-Ica mmm. wmm amour., or

aocnns'rna, Nnwonx, AssIeNoa 'ro ms'rlun" KODAKOOHANY, Ol' B .0GHE8TER, NEW YORK, .L CORPORATION OF NEW YORK l :noroemmc Application 'ma april' as,

This invention relates to a ltwo-color subi tractive photographic process of the type inf volving the use of supelgiosed diferentially color-sensitized layers. everal processes of 5 this type have been heretofore developed involving various features in common with the process here proposed. However, the procedure outlined here is found to give improved results .overthose previously suggest- 'ed and m invention resides in the artlcular combinatlon of steps claimed, whlch, when used together, give particularly sucoessfulreeasults. The process 1ncludes as necessall tures the use of ka material having di erentially sensitized layers in which there are developed silver images, andthereafter by color development diil'erentially colored dye and silver images, all the silver images being left in the la ers until the final step when they are dy simultaneously. By this series of Steps, I am enabled to obtain particularly good color separation between the layers and to simplify t e' process as a whole.4 Reference will now be made to the accom anyingY drawin in the several figures of w same caracters designate the same parts. All of the figures are sectional views on an exaggerated scale of a film used in my process and showing the images in the various stages of the procedure.

Fig. 1 indicates an unexposed Fig. 2V indicates the same ilm after exposure and the first development. Fig. 3 indicates the ilm after a Q5 posure and development.

Fig. 4 indicates Lthe finished product. Fig. 5 shows on an even more vexaggerated scale the position of the silver images at the ste indicated in Fig. 2, and bei 6 indicates the final product in a film second exin wich the ,order of thejlayers isv dierent" than in the preferred form. L 'M invention ma be more clearly under- ,stoo fromsthe fol owing complete description-of one embodiment.' v

A film su port S'is coated with two .emulsion layers element ma be made in the manner vdescribed in` my app i'cation Serial No. 559,347, filed August v25, A1931. The' two layers are speich the J Sodium sull/ite.

sensitive film.

' The temperature is maintained at 654 F.

and G in superposition. This coma rnocnss 190s. Y term no. 007,570.

ciicall sensitizedl to green and red r lower layer R is sensitized for red li ht by a.

non-diffusin specific red sensitizing Y ehaving a welleined minimum sensitizmg actionin the green. Such a dye is, for example, "4, 4 diphenyl 3, 3 dieth l7 (14*phenyl thiazoleethiodide) methyl thiazo ecarboc anne iodide. The upper layer G- is speclfically sensitized for green light by a green sensiseudocyanine iodide, is a good example.

sisting diffusion into the adjacent layer.

A lm so prepared is exposedto a colored ylight image in an ordinary camera or by printing from a color positive, a yellow filter being used to screen out the blue-violet por'-a tion of the spectrum to which both emulsion layers are sensitive. y

l The `film is treatedl as follows: It is de-I veloped seven minutes in a motion icture positive developer such as the following:

` Femmina No. I

'Water --l 40 liters Monomethyl p-aminophenol sulfate Hydroquinone T--- .240 grams Sodium carbonate 750 grams Pdtassium bromide 36 grams Citric acid 28v grams Potassium metabisulite The film is then washed for ten minutes. The'V condition of the film at this stage is indicated in Fig. 2, where there is shown in layer R a silver negative image r, this being the redy sensation record, and layer G a green sensation negative silver record g. f

Without removing support as indicated by the arrow in Fig. 2 for two seconds at, one footfrom-a. 15-watt 6,0 gramsy s fas the developed vnegative y silver imageythe film is exposed through the 12 grams .l 1600 grainsv ,la-mp through a ilter transmitting only deep l red light', to which only the unexposed salts .of layer R are sensitive. y It isnow developed ten minutes in the following blue-green color-forming developer,

formin a mixed silver and blue-green dye image in layer R.

FORMULA No. II

Sodium carbonate, 10% solu- A tion 4' liters Sodium sulfite v50.0 grams p-amino-diethyl-aniline hydrochloride 100.0 grams 3.5 dibromo-o-cresol 50 g. per

liter of 95% ethanol 2.0 liters 1Vater to 20 liters The film is again washed ten minutes.

At this point the iilm is fully exposed to white light and the remaining operations may be carried out in white light.

The film is now developed ten minutes in the following red color-forming developer,

forming a mixed silver and red dye image B' Solution-A is added to solution B and the resulting mixture is made up with water to 20 liters. A

The film is again washed ten minutes.

At this point the film lcontains silver images formed in all three of the developers mentioned, in addition to the two color images. These silver images are now removed by bleaching ten minutes in the following solution:

Litera Potassium bromide, 10% solution 1 Potassium ferricyani'de, 10% solution 1 Water to r 10 The film is then fixed in plain hypo, 30% solution, and is finally washed ten minutes and dried.

The advantage of allowing the silver-images to remain until the last step where two differentially lsensitized layers are used will now be more particularly pointed out. The

condition of the film after the completion of the first development isshown diagrammatically in the condition shown in Fig. 2, which is a much magnified cross-suction of the film. The black dots in the drawing represent grains of silverdeveloped in the non-staining developer; the masses of dots represent the images of exposures to colored light of graduated intensity. Since the original exposure and the penetration of the developer are both from above, these images tend to lie nearer the upper surface of each emulsion layer, penetrating farthest in those areas of greatest exposure. The remaining portions in the two emulsion layers represent unexposed and undeveloped silver bromide.

For correct color rendering the green developer should develop all those portions of the red sensitive layer, and of this layer only, that were not developed in the first developer. Strictly speaking, none of the green sensitive layer should develop. If it were possible to find red and green sensitizing dyes which had mutually exclusive sensitizing bands which did not overlap, this condition could be realized. In practice, however, such dyes are not available and it would be usually true that the sensitizing bands of the red and green sensitizers overlap somewhat and that there is a certain amount of diffusion of the sensitizers from one layer to an other in some stage of the process so that portions of the green sensitive layer may also be rendered developable by exposure to red light. This results in a certain amount of color degradation. By allowing the silver images, particularly the silver images developed in the two layers by the first or ordinary developer, to remain in the film and by exposing to red light from the support sido, as done in my invention,'it will be seen that the green sensitive layer is protected against thef action of the red light to a considerable extent. Referringto Fig. 5, the direction of the red light exposure is that indicated by the arrow. Av red sensationimage 1, a green sensation image 3,'and green and red sensation images constituting together `a white or neutral image 2 are shown as developed in the first non-staining developer. The underl ing silver of the red sensation image r in tlie redsensitive layer will screen the green sensitive layer from the action of red light. It is only -in any areas unoccupied by a red sensation image that the greensensitive layer will not-be protected. Thus, even if the green sensitive layer should bev somewhat sensitive to red light also,'as the result of diffusion of sensitizers or overlapping sensitivity bands, it will be protected against development in the green developer except in such areas as are not occupied by the redsensation. image.

This step results in a material improvement in the diierentiation of the green image,

assuring reasonably satisfactory color sepa-- ration. All that remains to be done after.

development of the green image is to ex pose the film fully to white light, develop the remaining silver bromide in a red color developer and remove the silver images-with suitable bleaches. v

-designatin g the same elements as in the other figures.

The described advantages obtained by leaving the negative silver ima e; in the film and applying the first colore light. exposure through the support are lost when the negative silver image is removed, as with a bi' chromate bleach prior to the second'exposure I consider as -included in myinvention all modifications and equivalents. coming within' the scope of the appended claims.

Having now described my invention, what I claim as new and desire to secure by `Letters s1lver ima es g a l also an image of a posing the element to light 'Patent is 1. The method of making a. multi-color record that comprises ex osure to a light image of an element carryln a plurality of differentially color sensitized layers, developing the affected portions to form uncolored exposing the element to light of a color capable of affecting only one of said layers", developing a silver and color image in the layer so exposed, exposing the element to white lght, developing in the other of said layers a silver and color image, then removing all said silver images in the several layers in a single operation, leaving a color image ineach layer.

2. The method of making a multi-color record that comprises exposure to a light im'- age of an element carrying two differentially color sensitized layers, developing the affect'- ed portions to form uncolored silver images, exposing the element to light of a color` capable of affecting only one'of` said layers, developing a silver and color image in the layer so exposed, exposing the element to white light, developing in the other of said layers a silver image and a color image different in color than that first develo d, and vthen removing allfour said silver lmages in the two. layers in a single bath leaving color images of different color in the two-layers.

3. The method of making a multi-color lrecord that comprises exposure to a light image of two differentially .color sensitized layers carried by a common support, devloping in an ordinary .developer the affected portions to form silver images; eX-

of a color capable of affecting only one of said layers, `developing-the' layer so exposed in a color developer forming' also sa silver image, ex sing to white light, developing the other lao color developer yielding a silverimage and color complementary to image of vvalso `a silver image,

yer v1n a record/ that comprises exposure toa light image of a sensitlzed element comprising a support, next the support a red sensitivey layer c and over said red sensitive layer a green sensitive layer,`developin in an Ordinar developer the affected portlons of both layers to form silver images,

layer is sensitive from the direction toward which said layer lies, developing said'layer in a color-forming developer which also forms a silver vimage, exposing to uniform white light, developing in a color-forming developer which forms a silver image and also yields a color complementary to that given by the first color` developer, vand finally exposing the element to uniform light of a color to which only onebleaching and removing all the silver images formed, leaving differently colored images in the layers.

5. The method of making a multi-color record that comprises. exposure to a light a sensitized element comprising a support, next the support a red sensitive layer and over said red sensitive layer a green sensitive layer, developing in yan ordinary developer the affected portions of both layers to form silver images, exposing the element to uniform light of a color to which only one layer is sensitive from a direction opposite to that from which the first exposure was applied, developing said layer in a develo 1'-I forming a silver and a color image, exposing touniform white light, developing in a color i developer which yields a silver image and also a color complementary to that given by Vthe first color developer, and finally bleaching and removing all of the silver images formed, leaving complementary colored images in the two layers.

6. The method of making a multi-color record that comprises exposure to a light image of'a sensitized element comprising a support, next the support a red sensitive layer and over said red sensitive layer a green sensitivelayer, developing in an ordinary developer the affected portions-of both layers .to form silver images, exposing the element from the vsupport side developing the red sensitive .layer in a b uegreen color developer forming also a silver image, exposing to uniform white li ht, developing in a red color developer orming removing all the silver images formed, leav ing blue-green and red images in the respective layers.

record that comprises exposure from the support side to alight image of a sensitized eleto uniform red li ht,

and finally bleaching and f 7.*The method of making a multi-color' ment comprising a support, next the support aV green sensitive layer and over said green sensitive layer a red sensitive layer, develop ing in an ordinary developer the aeted porltions of both layers to form silver images, exposing the element from the emulsion side to uniform red light, developing the red sensitive layer in a blue-green color developer l forming also a silver image, exposing to uniform white light, developing in a red color developer forming also a silver image, and finally bleaching and removing all the silver images formed, leaving red and blue-green images in the respective layers.

Signed at Rochester, New York this 19th day of April, 1932.

MERRILL WILMER SEYMOUR. 

